Effectiveness of screening colonoscopy in a community-based study

In 2002 screening colonoscopy was introduced in Germany for the prevention of colorectal cancer (CRC) and CRC mortality. Individuals took part in a prospective study from October 2002 until September 2005 performed at a single centre for gastroenterology. Histopathological data, surgical-pathological stages and further follow-up events were recorded until 31st of December 2006. For screened individuals without symptoms, the data obtained were compared to those from age-matched patients who presented with clinical symptoms/signs and who underwent colonoscopy during the same period in time. A total of 5066 individuals underwent screening colonoscopy. In this group, colorectal cancer was detected in 46 individuals (0.9%). Endoscopic treatment was considered adequate for 21 cancers. In this group of 46 patients, 94.5% were classified into UICC stages I-II by pathological staging. In 504 screened individuals, colorectal polyps were detected (12.2%) and removed by polypectomy. Of these polyps, 16 were classified as cancer, 496 as adenomas and 1 as a carcinoid tumour. High grade dysplasia was noted in 41 polyps (8.3% of adenomas). In comparison, 4099 symptomatic patients underwent colonoscopy. In this group 100 cancers (2.4%) were detected. Advanced malignant tumours were noted in 39% of these; endoscopic treatment was feasible in 16% of the cancers. As of December 2006, cancer-related deaths were observed in 20% of symptomatic patients with CRC. Screening colonoscopy detects colorectal cancers in the early stages. Given the favourable prognosis in these stages, screening can reduce CRC-related mortality.